DenysMedvid/pdf2htmlEX
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clean code

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This commit is contained in:
Lu Wang 2013-04-04 01:35:44 +08:00
parent ae35bb24b6
commit 7cc6f1efcd
3 changed files with 70 additions and 35 deletions
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91
src/HTMLRenderer/TextLineBuffer.cc
View File

@ -42,17 +42,22 @@ void HTMLRenderer::TextLineBuffer::append_unicodes(const Unicode * u, int l)
void HTMLRenderer::TextLineBuffer::append_offset(double width)
{
/*
* If the last offset is very thin, we can ignore it and directly use it
* But this should not happen often, and we will also filter near-zero offsets when outputting them
* So don't check it
*/
if((!offsets.empty()) && (offsets.back().start_idx == text.size()))
offsets.back().width += width;
else
offsets.push_back(Offset({text.size(), width}));
offsets.emplace_back(text.size(), width);
}
void HTMLRenderer::TextLineBuffer::append_state(void)
{
if(states.empty() || (states.back().start_idx != text.size()))
{
states.resize(states.size() + 1);
states.emplace_back();
states.back().start_idx = text.size();
states.back().hash_umask = 0;
}
@ -73,6 +78,7 @@ void HTMLRenderer::TextLineBuffer::flush(void)
return;
}
// remove unuseful states in the end
while((!states.empty()) && (states.back().start_idx >= text.size()))
states.pop_back();
@ -84,24 +90,27 @@ void HTMLRenderer::TextLineBuffer::flush(void)
return;
}
// optimize before output
optimize();
double max_ascent = 0;
for(auto iter = states.begin(); iter != states.end(); ++iter)
{
const auto & s = *iter;
max_ascent = max<double>(max_ascent, s.font_info->ascent * s.draw_font_size);
}
for(auto iter = states.begin(); iter != states.end(); ++iter)
iter->hash();
// Start Output
ostream & out = renderer->f_pages.fs;
{
// max_ascent determines the height of the div
double max_ascent = 0;
for(auto iter = states.begin(); iter != states.end(); ++iter)
{
double cur_ascent = iter->font_info->ascent * iter->draw_font_size;
if(cur_ascent > max_ascent)
max_ascent = cur_ascent;
iter->hash();
}
long long hid = renderer->height_manager.install(max_ascent);
long long lid = renderer->left_manager .install(x);
long long bid = renderer->bottom_manager.install(y);
// open <div> for the current text line
out << "<div class=\"" << CSS::LINE_CN
<< " " << CSS::TRANSFORM_MATRIX_CN << tm_id
<< " " << CSS::LEFT_CN << lid
@ -110,6 +119,7 @@ void HTMLRenderer::TextLineBuffer::flush(void)
<< "\">";
}
// a special safeguard in the bottom
stack.clear();
stack.push_back(nullptr);
@ -151,16 +161,19 @@ void HTMLRenderer::TextLineBuffer::flush(void)
if((*iter)->start_idx <= last_text_pos_with_negative_offset)
break;
}
// export the diff between *state_iter1 and stack.back()
state_iter1->begin(out, stack.back());
stack.push_back(&*state_iter1);
}
// [state_iter1->start_idx, text_idx2) are covered by the current state
size_t text_idx2 = (state_iter2 == states.end()) ? text.size() : state_iter2->start_idx;
// dump all text and offsets before next state
while(true)
{
if((cur_offset_iter != offsets.end()) && (cur_offset_iter->start_idx <= cur_text_idx))
if((cur_offset_iter != offsets.end())
&& (cur_offset_iter->start_idx <= cur_text_idx))
{
if(cur_offset_iter->start_idx > text_idx2)
break;
@ -168,6 +181,7 @@ void HTMLRenderer::TextLineBuffer::flush(void)
double target = cur_offset_iter->width + dx;
double actual_offset = 0;
//ignore near-zero offsets
if(abs(target) <= renderer->param->h_eps)
{
actual_offset = 0;
@ -175,6 +189,7 @@ void HTMLRenderer::TextLineBuffer::flush(void)
else
{
bool done = false;
// check if the offset is equivalent to a single ' '
if(!(state_iter1->hash_umask & State::umask_by_id(State::WORD_SPACE_ID)))
{
double space_off = state_iter1->single_space_offset();
@ -187,6 +202,7 @@ void HTMLRenderer::TextLineBuffer::flush(void)
}
}
// finally, just dump it
if(!done)
{
long long wid = renderer->whitespace_manager.install(target, &actual_offset);
@ -236,6 +252,8 @@ void HTMLRenderer::TextLineBuffer::flush(void)
void HTMLRenderer::TextLineBuffer::set_state (State & state)
{
// TODO: as letter_space and word_space may be modified (optimization)
// we should not install them so early
state.ids[State::FONT_ID] = renderer->cur_font_info->id;
state.ids[State::FONT_SIZE_ID] = renderer->font_size_manager.get_id();
state.ids[State::FILL_COLOR_ID] = renderer->fill_color_manager.get_id();
@ -284,25 +302,28 @@ void HTMLRenderer::TextLineBuffer::optimize()
{
const size_t text_idx1 = state_iter1->start_idx;
const size_t text_idx2 = (state_iter2 == states.end()) ? text.size() : state_iter2->start_idx;
// get the text segment covered by current state (*state_iter1)
const auto text_iter1 = text.begin() + text_idx1;
const auto text_iter2 = text.begin() + text_idx2;
size_t text_count = text_idx2 - text_idx1;
while((offset_iter1 != offsets.end()) && (offset_iter1->start_idx <= text_idx1))
// there might be some offsets before the first state
while((offset_iter1 != offsets.end())
&& (offset_iter1->start_idx <= text_idx1))
{
new_offsets.push_back(*(offset_iter1++));
}
// find the last offset covered by the current state
auto offset_iter2 = offset_iter1;
for(; (offset_iter2 != offsets.end()) && (offset_iter2->start_idx <= text_idx2); ++offset_iter2) { }
// There are `offset_count` <span>'s, the target is to reduce this number
size_t offset_count = offset_iter2 - offset_iter1;
assert(text_count >= offset_count);
double letter_space_diff = 0; // will be later used for optimizing word space
width_map.clear();
// Optimize letter space
// how much letter_space is changed
// will be later used for optimizing word space
double letter_space_diff = 0;
width_map.clear();
// In some PDF files all letter spaces are implemented as position shifts between each letter
// try to simplify it with a proper letter space
@ -325,7 +346,9 @@ void HTMLRenderer::TextLineBuffer::optimize()
width_map.insert(iter, std::make_pair(target, 1));
}
}
// TODO snapping the widths may result a better result
// e.g. for (-0.7 0.6 -0.2 0.3 10 10), 0 is better than 10
double most_used_width = 0;
size_t max_count = 0;
for(auto iter = width_map.begin(); iter != width_map.end(); ++iter)
@ -342,7 +365,7 @@ void HTMLRenderer::TextLineBuffer::optimize()
if(max_count <= text_count / 2)
{
// the old value is the best
// just copy copy offsets
// just copy old offsets
new_offsets.insert(new_offsets.end(), offset_iter1, offset_iter2);
}
else
@ -369,7 +392,7 @@ void HTMLRenderer::TextLineBuffer::optimize()
}
if(!equal(cur_width, 0))
{
new_offsets.push_back(Offset({cur_text_idx+1, cur_width}));
new_offsets.emplace_back(cur_text_idx+1, cur_width);
++ offset_count;
}
}
@ -382,6 +405,10 @@ void HTMLRenderer::TextLineBuffer::optimize()
// We may try to change (some of) them to ' ' by adjusting word_space
// for now, we cosider only the no-space scenario
// which also includes the case when param->space_as_offset is set
// get the text segment covered by current state (*state_iter1)
const auto text_iter1 = text.begin() + text_idx1;
const auto text_iter2 = text.begin() + text_idx2;
if(find(text_iter1, text_iter2, ' ') == text_iter2)
{
// if there is not any space, we may change the value of word_space arbitrarily
@ -399,7 +426,7 @@ void HTMLRenderer::TextLineBuffer::optimize()
// find the most frequent width, with new letter space applied
for(auto iter = width_map.begin(); iter != width_map.end(); ++iter)
{
double fixed_width = iter->first + letter_space_diff;
double fixed_width = iter->first + letter_space_diff; // this is the actual offset in HTML
// we don't want to add spaces for tiny gaps, or even negative shifts
if((fixed_width >= threshold - EPS) && (iter->second > max_count))
{
@ -408,18 +435,14 @@ void HTMLRenderer::TextLineBuffer::optimize()
}
}
state_iter1->word_space = 0;
state_iter1->word_space = 0; // clear word_space for single_space_offset
double new_word_space = most_used_width - state_iter1->single_space_offset();
// install new word_space
state_iter1->ids[State::WORD_SPACE_ID] = ws_manager.install(new_word_space, &(state_iter1->word_space));
// mark that the word_space is not free
state_iter1->hash_umask &= (~word_space_umask);
state_iter1->ids[State::WORD_SPACE_ID] = ws_manager.install(new_word_space, &(state_iter1->word_space)); // install new word_space
state_iter1->hash_umask &= (~word_space_umask); // mark that the word_space is not free
}
else
else // there is no offset at all
{
// if there is no offset at all
// we just free word_space
state_iter1->hash_umask |= word_space_umask;
state_iter1->hash_umask |= word_space_umask; // we just free word_space
}
}
offset_iter1 = offset_iter2;

3
src/HTMLRenderer/TextLineBuffer.h
View File

@ -67,6 +67,9 @@ public:
class Offset {
public:
Offset(size_t size_idx, double width)
:start_idx(size_idx),width(width)
{ }
size_t start_idx; // should put this Offset right before text[start_idx];
double width;
};

11
src/HTMLRenderer/text.cc
View File

@ -74,8 +74,17 @@ void HTMLRenderer::drawString(GfxState * state, GooString * s)
bool is_space = false;
if (n == 1 && *p == ' ')
{
++nSpaces;
/*
* This is by standard
* however some PDF will use ' ' as a normal encoding slot
* such that it will be mapped to other unicodes
* In that case, when sapce_as_offset is on, we will simply ignore that character...
*
* Checking mapped unicode may or may not work
* There are always ugly PDF files with no usefull info at all.
*/
is_space = true;
++nSpaces;
}
if(is_space && (param->space_as_offset))